Oil and natural gas will still make up more than half of the world's energy mix in 2050 despite efforts to transition away from fossil fuels, according to a forecast published by Exxon Mobil on Monday.Fossil fuels currently represent about 80% of the world energy mix, according to the Paris-based International Energy Agency. Oil demand will plateau after 2030 but remain roughly at current levels of more than 100 million barrels per day through 2050, according to Exxon's forecast.Stubborn oil and gas demand ...